92 ALFALFA FARMING IN AMERICA. 
should not be depastured; indeed, after killing frost 
no animal should be permitted to set foot in the 
alfalfa field. The difference in thrift and production 
between late mown alfalfa and that given fair treat- 
ment is very marked indeed. Many plants mown 
off in October will die altogether during the follow- 
ing winter. Thus when one means to plow the field, 
it is wise to mow it as late as convenient, since he 
gets quite a little hay from this fourth or fifth cut- 
ting, and at the same time weakens his alfalfa so 
that it plows easier. Very great injury in the humid 
regions has unknowingly been done the alfalfa by 
this very ignorance of its nature that led to its being 
mown late or depastured until winter. 
Danger from Treading.—In dry countries it seems 
to do little injury to alfalfa to let animals run on it 
all winter, even though they tread it down into the 
dust. In all the region of America lying east of the 
Missouri River it is most harmful to alfalfa to tread 
upon it in winter, either by the feet of men or ani- 
mals, or by wagons going over it. The line of direc- 
tion of a farm wagon going across a field can often 
be distinctly traced next spring by the two streaks 
of dead alfalfa plants. 
An alfalfa field should be a sacred place. Its gates 
should be closed and locked in September and not re- 
opened till May at the earliest, probably not till the 
first day of June, though these dates will of course 
be dependent on the latitude, now having in mind 
the climate of about parallel of latitude 40. 
Hardiness of the Plant.—Alfalfa then is one of 
